Support BackendV2 (#1875)

* Support backendv2

* Change API of aerbackend init

* fix lint

* Fix lint

* Add reset gate

* Return None if the configuration does not have max_experiments

* Change function to constant

* Update code to pass the test

* Remove print

* Fix lint

* Change num of qubits in Estimator

* Skip transpilation

* Change transpile optimization level

* Add release notes

* Change process of cirucit compose by the number of qubits in estimator

* use passmanager for measurement circuits

* refactor (change line order)

* Fix lint

* Add a detail description to the release note

---------

Co-authored-by: ikkoham <[email protected]>
Co-authored-by: Hiroshi Horii <[email protected]>
Co-authored-by: Jun Doi <[email protected]>
Co-authored-by: Matthew Treinish <[email protected]>

qiskit_aer/backends/aer_simulator.py

@@ -31,7 +31,7 @@
     BASIS_GATES,
 )
 
-# pylint: disable=import-error, no-name-in-module
+# pylint: disable=import-error, no-name-in-module, abstract-method
 from .controller_wrappers import aer_controller_execute
 
 logger = logging.getLogger(__name__)
@@ -784,7 +784,7 @@ def __repr__(self):
         pad = " " * (len(self.__class__.__name__) + 1)
         return f"{display[:-1]}\n{pad}noise_model={repr(noise_model)})"
 
-    def name(self):
+    def _name(self):
         """Format backend name string for simulator"""
         name = self._configuration.backend_name
         method = getattr(self.options, "method", None)
@@ -813,6 +813,7 @@ def from_backend(cls, backend, **options):
                 max_shots=int(1e6),
                 coupling_map=list(backend.coupling_map.get_edges()),
                 max_experiments=backend.max_circuits,
+                description=backend.description,
             )
             properties = target_to_backend_properties(backend.target)
         elif isinstance(backend, BackendV1):
@@ -866,7 +867,7 @@ def configuration(self):
         ]
         config.basis_gates = self._cached_basis_gates + config.custom_instructions
         # Update simulator name
-        config.backend_name = self.name()
+        config.backend_name = self._name()
         return config
 
     def _execute_circuits(self, aer_circuits, noise_model, config):

qiskit_aer/backends/aerbackend.py

@@ -23,7 +23,8 @@
 
 from qiskit.circuit import QuantumCircuit, ParameterExpression, Delay
 from qiskit.compiler import assemble
-from qiskit.providers import BackendV1 as Backend
+from qiskit.providers import BackendV2 as Backend
+from qiskit.providers import convert_to_target
 from qiskit.providers.models import BackendStatus
 from qiskit.pulse import Schedule, ScheduleBlock
 from qiskit.qobj import QasmQobj, PulseQobj
@@ -34,8 +35,9 @@
 from ..noise.errors.quantum_error import QuantumChannelInstruction
 from .aer_compiler import compile_circuit, assemble_circuits, generate_aer_config
 from .backend_utils import format_save_type, circuit_optypes
+from .name_mapping import NAME_MAPPING
 
-# pylint: disable=import-error, no-name-in-module
+# pylint: disable=import-error, no-name-in-module, abstract-method
 from .controller_wrappers import AerConfig
 
 # Logger
@@ -67,16 +69,24 @@ def __init__(
         # Init configuration and provider in Backend
         configuration.simulator = True
         configuration.local = True
-        super().__init__(configuration, provider=provider)
+        super().__init__(
+            provider=provider,
+            name=configuration.backend_name,
+            description=configuration.description,
+            backend_version=configuration.backend_version,
+        )
 
         # Initialize backend properties and pulse defaults.
         self._properties = properties
         self._defaults = defaults
+        self._configuration = configuration
 
         # Custom option values for config, properties, and defaults
         self._options_configuration = {}
         self._options_defaults = {}
         self._options_properties = {}
+        self._target = None
+        self._mapping = NAME_MAPPING
 
         # Set options from backend_options dictionary
         if backend_options is not None:
@@ -332,9 +342,19 @@ def defaults(self):
             setattr(defaults, key, val)
         return defaults
 
-    @classmethod
-    def _default_options(cls):
-        pass
+    @property
+    def max_circuits(self):
+        if hasattr(self.configuration(), "max_experiments"):
+            return self.configuration().max_experiments
+        else:
+            return None
+
+    @property
+    def target(self):
+        self._target = convert_to_target(
+            self.configuration(), self.properties(), self.defaults(), self._mapping
+        )
+        return self._target
 
     def clear_options(self):
         """Reset the simulator options to default values."""
@@ -350,7 +370,7 @@ def status(self):
             BackendStatus: the status of the backend.
         """
         return BackendStatus(
-            backend_name=self.name(),
+            backend_name=self.name,
             backend_version=self.configuration().backend_version,
             operational=True,
             pending_jobs=0,
@@ -388,15 +408,15 @@ def _execute_qobj_job(self, qobj, job_id="", format_result=True):
 
         # Validate output
         if not isinstance(output, dict):
-            logger.error("%s: simulation failed.", self.name())
+            logger.error("%s: simulation failed.", self.name)
             if output:
                 logger.error("Output: %s", output)
             raise AerError("simulation terminated without returning valid output.")
 
         # Format results
         output["job_id"] = job_id
         output["date"] = datetime.datetime.now().isoformat()
-        output["backend_name"] = self.name()
+        output["backend_name"] = self.name
         output["backend_version"] = self.configuration().backend_version
 
         # Push metadata to experiment headers
@@ -454,15 +474,15 @@ def _execute_circuits_job(
 
         # Validate output
         if not isinstance(output, dict):
-            logger.error("%s: simulation failed.", self.name())
+            logger.error("%s: simulation failed.", self.name)
             if output:
                 logger.error("Output: %s", output)
             raise AerError("simulation terminated without returning valid output.")
 
         # Format results
         output["job_id"] = job_id
         output["date"] = datetime.datetime.now().isoformat()
-        output["backend_name"] = self.name()
+        output["backend_name"] = self.name
         output["backend_version"] = self.configuration().backend_version
 
         # Push metadata to experiment headers
@@ -725,5 +745,5 @@ def _set_defaults_option(self, key, value):
     def __repr__(self):
         """String representation of an AerBackend."""
         name = self.__class__.__name__
-        display = f"'{self.name()}'"
+        display = f"'{self.name}'"
         return f"{name}({display})"

qiskit_aer/backends/backend_utils.py

@@ -109,6 +109,7 @@
             "pauli",
             "mcx_gray",
             "ecr",
+            "reset",
             "switch_case",
         ]
     ),
@@ -150,6 +151,7 @@
             "delay",
             "pauli",
             "ecr",
+            "reset",
             "switch_case",
         ]
     ),
@@ -193,6 +195,7 @@
             "cswap",
             "diagonal",
             "initialize",
+            "reset",
             "switch_case",
         ]
     ),
@@ -213,6 +216,7 @@
             "swap",
             "delay",
             "pauli",
+            "reset",
             "ecr",
             "rx",
             "ry",
@@ -243,6 +247,7 @@
             "ccz",
             "delay",
             "pauli",
+            "reset",
         ]
     ),
     "unitary": sorted(
@@ -304,6 +309,7 @@
             "delay",
             "pauli",
             "ecr",
+            "reset",
         ]
     ),
     "superop": sorted(
@@ -343,6 +349,7 @@
             "diagonal",
             "delay",
             "pauli",
+            "reset",
         ]
     ),
     "tensor_network": sorted(
@@ -405,6 +412,7 @@
             "delay",
             "pauli",
             "mcx_gray",
+            "reset",
         ]
     ),
 }